1. Field of the Invention
The present invention relates to two-wire transmitters. More specifically, the present invention is directed to a two-wire transmitter used for detecting process variables and transmitted signals representative of the detected variable onto a two-wire transmission line.
2. Description of the Prior Art
Conventionally when a process variable, e.g., a flow rate in a process control system is to be measured from a differential pressure across an orifice, compensation of the detected pressure signals must be performed in order to obtain correct data by considering the influence thereon by temperature and static pressure. Therefore, different loops are provided for differential pressure, static pressure, and temperature transmitters, and signals from the respective transmitters are sequentially supplied to and processed by an arithmetic operation unit. With such a conventional arrangement, different transmitters and associated loops are required for different compensations, resulting in a considerably expensive system. Accordingly, it would be desirable to provide a single loop two-wire transmitter capable of effecting static pressure and temperature compensation.